[]
Gets or sets the descriptive (alternative) text string for the specified shape object.
Setting a non-empty alternative text clears the decorative flag for the shape.
string AlternativeText { get; set; }
Property AlternativeText As String
IShape shape = worksheet.Shapes.AddShape(AutoShapeType.Rectangle, 20, 20, 120, 60);
shape.AlternativeText = "Company logo";
string alternativeText = shape.AlternativeText;